night前面用介词at或in，构成短语at night、in the night，意思是在晚上。

at night

在晚间;在夜里;晚间;晚上;

in the night

在晚上;在夜里;在夜晚;在夜间;

In the night all cats are grey.夜里猫都呈灰色。

A shot rang out in the night.半夜响起一声枪声。

I was sick three times in the night.我夜里呕吐了3次。

I woke up twice in the night.我夜里醒过两次。

He dared not go there at night.晚上他不敢到那里去。

It was late at night,and all was quiet in the village.夜深了，村子里沉静下来。